1. Technical Field
The invention relates to route planning systems. More particularly, the invention relates to a method and apparatus for two-stage route planning systems.
2. Description of the Background Art
Route planning is critical for autonomous vehicles. For purposes of the discussion herein, an autonomous vehicle, also known as a robotic car, or informally as driverless or self-driving, is a vehicle that is capable of fulfilling the human transportation capabilities of a traditional vehicle. As an autonomous vehicle, it is capable of sensing its environment and navigating without human input. Robotic cars exist mainly as prototypes, but are likely to become more widespread in the near future. Autonomous vehicles sense their surroundings with such techniques as radar, LIDAR, GPS, and computer vision. Advanced control systems interpret sensory information to identify appropriate navigation paths, as well as obstacles and relevant signage. Some autonomous vehicles update their maps based on sensory input, allowing them to find their way through uncharted environments.
Since the late 2000s, significant advances have been made in both technology and legislation relevant to autonomous vehicles. Numerous major companies and research organizations have developed working prototype autonomous vehicles, including Google, Continental Automotive Systems, Bosch, Nissan, Toyota, Audi, and Oxford University. In June 2011, the state of Nevada was the first jurisdiction in the United States to pass a law concerning the operation of autonomous vehicles. The Nevada law went into effect on Mar. 1, 2012.
It would be advantageous to provide a highly efficient and precise route planning system. Such system would be especially useful for autonomous vehicles, e.g. so-called self-driving or robotic vehicles.